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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             P A R . U T I L                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --

-- http://www.gnu.org/licenses for a complete copy of the license.          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

with Csets;    use Csets;

with Namet.Sp; use Namet.Sp;

with Stylesw;  use Stylesw;

with Uintp;    use Uintp;

with GNAT.Spelling_Checker; use GNAT.Spelling_Checker;

separate (Par)

package body Util is

   ---------------------

   -- Bad_Spelling_Of --

   ---------------------

   function Bad_Spelling_Of (T : Token_Type) return Boolean is

      Tname : constant String := Token_Type'Image (T);

      --  Characters of token name

      S : String (1 .. Tname'Last - 4);

      --  Characters of token name folded to lower case, omitting TOK_ at start

      M1 : String (1 .. 42) := "incorrect spelling of keyword ************";

      M2 : String (1 .. 44) := "illegal abbreviation of keyword ************";

      --  Buffers used to construct error message

      P1 : constant := 30;

      P2 : constant := 32;

      --  Starting subscripts in M1, M2 for keyword name

      SL : constant Natural := S'Length;

      --  Length of expected token name excluding TOK_ at start

   begin

      if Token /= Tok_Identifier then

         return False;

      end if;

      for J in S'Range loop

         S (J) := Fold_Lower (Tname (J + 4));

      end loop;

      Get_Name_String (Token_Name);

      --  A special check for case of PROGRAM used for PROCEDURE

      if T = Tok_Procedure

        and then Name_Len = 7

        and then Name_Buffer (1 .. 7) = "program"

      then

         Error_Msg_SC -- CODEFIX

           ("PROCEDURE expected");

         Token := T;

         return True;

      --  A special check for an illegal abbreviation

      elsif Name_Len < S'Length

        and then Name_Len >= 4

        and then Name_Buffer (1 .. Name_Len) = S (1 .. Name_Len)

      then

         for J in 1 .. S'Last loop

            M2 (P2 + J - 1) := Fold_Upper (S (J));

         end loop;

         Error_Msg_SC (M2 (1 .. P2 - 1 + S'Last));

         Token := T;

         return True;

      end if;

      --  Now we go into the full circuit to check for a misspelling

      --  Never consider something a misspelling if either the actual or

      --  expected string is less than 3 characters (before this check we

      --  used to consider i to be a misspelled if in some cases!)

      if SL < 3 or else Name_Len < 3 then

         return False;

      --  Special case: prefix matches, i.e. the leading characters of the

      --  token that we have exactly match the required keyword. If there

      --  are at least two characters left over, assume that we have a case

      --  of two keywords joined together which should not be joined.

      elsif Name_Len > SL + 1

        and then S = Name_Buffer (1 .. SL)

      then

         Scan_Ptr := Token_Ptr + S'Length;

         Error_Msg_S ("|missing space");

         Token := T;

         return True;

      end if;

      if Is_Bad_Spelling_Of (Name_Buffer (1 .. Name_Len), S) then

         for J in 1 .. S'Last loop

            M1 (P1 + J - 1) := Fold_Upper (S (J));

         end loop;

         Error_Msg_SC -- CODFIX

           (M1 (1 .. P1 - 1 + S'Last));

         Token := T;

         return True;

      else

         return False;

      end if;

   end Bad_Spelling_Of;

   ----------------------

   -- Check_95_Keyword --

   ----------------------

   --  On entry, the caller has checked that current token is an identifier

   --  whose name matches the name of the 95 keyword New_Tok.

   procedure Check_95_Keyword (Token_95, Next : Token_Type) is

      Scan_State : Saved_Scan_State;

   begin

      Save_Scan_State (Scan_State); -- at identifier/keyword

      Scan; -- past identifier/keyword

      if Token = Next then

         Restore_Scan_State (Scan_State); -- to identifier

         Error_Msg_Name_1 := Token_Name;

         Error_Msg_SC ("(Ada 83) keyword* cannot be used!");

         Token := Token_95;

      else

         Restore_Scan_State (Scan_State); -- to identifier

      end if;

   end Check_95_Keyword;

   ----------------------

   -- Check_Bad_Layout --

   ----------------------

   procedure Check_Bad_Layout is

   begin

      if RM_Column_Check and then Token_Is_At_Start_Of_Line

        and then Start_Column <= Scope.Table (Scope.Last).Ecol

      then

         Error_Msg_BC -- CODEFIX

           ("(style) incorrect layout");

      end if;

   end Check_Bad_Layout;

   --------------------------

   -- Check_Future_Keyword --

   --------------------------

   procedure Check_Future_Keyword is

   begin

      --  Ada 2005 (AI-284): Compiling in Ada 95 mode we warn that INTERFACE,

      --  OVERRIDING, and SYNCHRONIZED are new reserved words.

      if Ada_Version = Ada_95

        and then Warn_On_Ada_2005_Compatibility

      then

         if Token_Name = Name_Overriding

           or else Token_Name = Name_Synchronized

           or else (Token_Name = Name_Interface

                     and then Prev_Token /= Tok_Pragma)

         then

            Error_Msg_N ("& is a reserved word in Ada 2005?", Token_Node);

         end if;

      end if;

      --  Similarly, warn about Ada 2012 reserved words

      if Ada_Version in Ada_95 .. Ada_2005

        and then Warn_On_Ada_2012_Compatibility

      then

         if Token_Name = Name_Some then

            Error_Msg_N ("& is a reserved word in Ada 2012?", Token_Node);

         end if;

      end if;

      --  Note: we deliberately do not emit these warnings when operating in

      --  Ada 83 mode because in that case we assume the user is building

      --  legacy code anyway and is not interested in updating Ada versions.

   end Check_Future_Keyword;

   --------------------------

   -- Check_Misspelling_Of --

   --------------------------

   procedure Check_Misspelling_Of (T : Token_Type) is

   begin

      if Bad_Spelling_Of (T) then

         null;

      end if;

   end Check_Misspelling_Of;

   -----------------------------

   -- Check_Simple_Expression --

   -----------------------------

   procedure Check_Simple_Expression (E : Node_Id) is

   begin

      if Expr_Form = EF_Non_Simple then

         Error_Msg_N ("this expression must be parenthesized", E);

      end if;

   end Check_Simple_Expression;

   ---------------------------------------

   -- Check_Simple_Expression_In_Ada_83 --

   ---------------------------------------

   procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id) is

   begin

      if Expr_Form = EF_Non_Simple then

         if Ada_Version = Ada_83 then

            Error_Msg_N ("(Ada 83) this expression must be parenthesized!", E);

         end if;

      end if;

   end Check_Simple_Expression_In_Ada_83;

   ------------------------

   -- Check_Subtype_Mark --

   ------------------------

   function Check_Subtype_Mark (Mark : Node_Id) return Node_Id is

   begin

      if Nkind (Mark) = N_Identifier

        or else Nkind (Mark) = N_Selected_Component

        or else (Nkind (Mark) = N_Attribute_Reference

                  and then Is_Type_Attribute_Name (Attribute_Name (Mark)))

        or else Mark = Error

      then

         return Mark;

      else

         Error_Msg ("subtype mark expected", Sloc (Mark));

         return Error;

      end if;

   end Check_Subtype_Mark;

   -------------------

   -- Comma_Present --

   -------------------

   function Comma_Present return Boolean is

      Scan_State  : Saved_Scan_State;

      Paren_Count : Nat;

   begin

      --  First check, if a comma is present, then a comma is present!

      if Token = Tok_Comma then

         T_Comma;

         return True;

      --  If we have a right paren, then that is taken as ending the list

      --  i.e. no comma is present.

      elsif Token = Tok_Right_Paren then

         return False;

      --  If pragmas, then get rid of them and make a recursive call

      --  to process what follows these pragmas.

      elsif Token = Tok_Pragma then

         P_Pragmas_Misplaced;

         return Comma_Present;

      --  At this stage we have an error, and the goal is to decide on whether

      --  or not we should diagnose an error and report a (non-existent)

      --  comma as being present, or simply to report no comma is present

      --  If we are a semicolon, then the question is whether we have a missing

      --  right paren, or whether the semicolon should have been a comma. To

      --  guess the right answer, we scan ahead keeping track of the paren

      --  level, looking for a clue that helps us make the right decision.

      --  This approach is highly accurate in the single error case, and does

      --  not make bad mistakes in the multiple error case (indeed we can't

      --  really make a very bad decision at this point in any case).

      elsif Token = Tok_Semicolon then

         Save_Scan_State (Scan_State);

         Scan; -- past semicolon

         --  Check for being followed by identifier => which almost certainly

         --  means we are still in a parameter list and the comma should have

         --  been a semicolon (such a sequence could not follow a semicolon)

         if Token = Tok_Identifier then

            Scan;

            if Token = Tok_Arrow then

               goto Assume_Comma;

            end if;

         end if;

         --  If that test didn't work, loop ahead looking for a comma or

         --  semicolon at the same parenthesis level. Always remember that

         --  we can't go badly wrong in an error situation like this!

         Paren_Count := 0;

         --  Here is the look ahead loop, Paren_Count tells us whether the

         --  token we are looking at is at the same paren level as the

         --  suspicious semicolon that we are trying to figure out.

         loop

            --  If we hit another semicolon or an end of file, and we have

            --  not seen a right paren or another comma on the way, then

            --  probably the semicolon did end the list. Indeed that is

            --  certainly the only single error correction possible here.

            if Token = Tok_Semicolon or else Token = Tok_EOF then

               Restore_Scan_State (Scan_State);

               return False;

            --  A comma at the same paren level as the semicolon is a strong

            --  indicator that the semicolon should have been a comma, indeed

            --  again this is the only possible single error correction.

            elsif Token = Tok_Comma then

               exit when Paren_Count = 0;

            --  A left paren just bumps the paren count

            elsif Token = Tok_Left_Paren then

               Paren_Count := Paren_Count + 1;

            --  A right paren that is at the same paren level as the semicolon

            --  also means that the only possible single error correction is

            --  to assume that the semicolon should have been a comma. If we

            --  are not at the same paren level, then adjust the paren level.

            elsif Token = Tok_Right_Paren then

               exit when Paren_Count = 0;

               Paren_Count := Paren_Count - 1;

            end if;

            --  Keep going, we haven't made a decision yet

            Scan;

         end loop;

         --  If we fall through the loop, it means that we found a terminating

         --  right paren or another comma. In either case it is reasonable to

         --  assume that the semicolon was really intended to be a comma. Also

         --  come here for the identifier arrow case.

         <<Assume_Comma>>

            Restore_Scan_State (Scan_State);

            Error_Msg_SC -- CODEFIX

              ("|"";"" should be "",""");

            Scan; -- past the semicolon

            return True;

      --  If we are not at semicolon or a right paren, then we base the

      --  decision on whether or not the next token can be part of an

      --  expression. If not, then decide that no comma is present (the

      --  caller will eventually generate a missing right parent message)

      elsif Token in Token_Class_Eterm then

         return False;

      --  Otherwise we assume a comma is present, even if none is present,

      --  since the next token must be part of an expression, so if we were

      --  at the end of the list, then there is more than one error present.

      else

         T_Comma; -- to give error

         return True;

      end if;

   end Comma_Present;

   -----------------------

   -- Discard_Junk_List --

   -----------------------

   procedure Discard_Junk_List (L : List_Id) is

      pragma Warnings (Off, L);

   begin

      null;

   end Discard_Junk_List;

   -----------------------

   -- Discard_Junk_Node --

   -----------------------

   procedure Discard_Junk_Node (N : Node_Id) is

      pragma Warnings (Off, N);

   begin

      null;

   end Discard_Junk_Node;

   ------------

   -- Ignore --

   ------------

   procedure Ignore (T : Token_Type) is

   begin

      while Token = T loop

         if T = Tok_Comma then

            Error_Msg_SC -- CODEFIX

              ("|extra "","" ignored");

         elsif T = Tok_Left_Paren then

            Error_Msg_SC -- CODEFIX

              ("|extra ""("" ignored");

         elsif T = Tok_Right_Paren then

            Error_Msg_SC -- CODEFIX

              ("|extra "")"" ignored");

         elsif T = Tok_Semicolon then

            Error_Msg_SC -- CODEFIX

              ("|extra "";"" ignored");

         elsif T = Tok_Colon then

            Error_Msg_SC -- CODEFIX

              ("|extra "":"" ignored");

         else

            declare

               Tname : constant String := Token_Type'Image (Token);

            begin

               Error_Msg_SC ("|extra " & Tname (5 .. Tname'Last) & "ignored");

            end;

         end if;

         Scan; -- Scan past ignored token

      end loop;

   end Ignore;

   ----------------------------

   -- Is_Reserved_Identifier --

   ----------------------------

   function Is_Reserved_Identifier (C : Id_Check := None) return Boolean is

   begin

      if not Is_Reserved_Keyword (Token) then

         return False;

      else

         declare

            Ident_Casing : constant Casing_Type :=

                             Identifier_Casing (Current_Source_File);

            Key_Casing   : constant Casing_Type :=

                             Keyword_Casing (Current_Source_File);

         begin

            --  If the casing of identifiers and keywords is different in

            --  this source file, and the casing of this token matches the

            --  keyword casing, then we return False, since it is pretty

            --  clearly intended to be a keyword.

            if Ident_Casing = Unknown

              or else Key_Casing = Unknown

              or else Ident_Casing = Key_Casing

              or else Determine_Token_Casing /= Key_Casing

            then

               return True;

            --  Here we have a keyword written clearly with keyword casing.

            --  In default mode, we would not be willing to consider this as

            --  a reserved identifier, but if C is set, we may still accept it

            elsif C /= None then

               declare

                  Scan_State  : Saved_Scan_State;

                  OK_Next_Tok : Boolean;

               begin

                  Save_Scan_State (Scan_State);

                  Scan;

                  if Token_Is_At_Start_Of_Line then

                     return False;

                  end if;

                  case C is

                     when None =>

                        raise Program_Error;

                     when C_Comma_Right_Paren =>

                        OK_Next_Tok :=

                          Token = Tok_Comma or else Token = Tok_Right_Paren;

                     when C_Comma_Colon =>

                        OK_Next_Tok :=

                          Token = Tok_Comma or else Token = Tok_Colon;

                     when C_Do =>

                        OK_Next_Tok :=

                          Token = Tok_Do;

                     when C_Dot =>

                        OK_Next_Tok :=

                          Token = Tok_Dot;

                     when C_Greater_Greater =>

                        OK_Next_Tok :=

                          Token = Tok_Greater_Greater;

                     when C_In =>

                        OK_Next_Tok :=

                          Token = Tok_In;

                     when C_Is =>

                        OK_Next_Tok :=

                          Token = Tok_Is;

                     when C_Left_Paren_Semicolon =>

                        OK_Next_Tok :=

                          Token = Tok_Left_Paren or else Token = Tok_Semicolon;

                     when C_Use =>

                        OK_Next_Tok :=

                          Token = Tok_Use;

                     when C_Vertical_Bar_Arrow =>

                        OK_Next_Tok :=

                          Token = Tok_Vertical_Bar or else Token = Tok_Arrow;

                  end case;

                  Restore_Scan_State (Scan_State);

                  if OK_Next_Tok then

                     return True;

                  end if;

               end;

            end if;

         end;

      end if;

      --  If we fall through it is not a reserved identifier

      return False;

   end Is_Reserved_Identifier;

   ----------------------

   -- Merge_Identifier --

   ----------------------

   procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type) is

   begin

      if Token /= Tok_Identifier then

         return;

      end if;

      declare

         S : Saved_Scan_State;

         T : Token_Type;

      begin

         Save_Scan_State (S);

         Scan;

         T := Token;

         Restore_Scan_State (S);

         if T /= Nxt then

            return;

         end if;

      end;

      --  Check exactly one space between identifiers

      if Source (Token_Ptr - 1) /= ' '

        or else Int (Token_Ptr) /=

                  Int (Prev_Token_Ptr) + Length_Of_Name (Chars (Prev)) + 1

      then

         return;

      end if;

      --  Do the merge

      Get_Name_String (Chars (Token_Node));

      declare

         Buf : constant String (1 .. Name_Len) :=

                 Name_Buffer (1 .. Name_Len);

      begin

         Get_Name_String (Chars (Prev));

         Add_Char_To_Name_Buffer ('_');

         Add_Str_To_Name_Buffer (Buf);

         Set_Chars (Prev, Name_Find);

      end;

      Error_Msg_Node_1 := Prev;

      Error_Msg_SC ("unexpected identifier, possibly & was meant here");

      Scan;

   end Merge_Identifier;

   -------------------

   -- Next_Token_Is --

   -------------------

   function Next_Token_Is (Tok : Token_Type) return Boolean is

      Scan_State : Saved_Scan_State;

      Result     : Boolean;

   begin

      Save_Scan_State (Scan_State);

      Scan;

      Result := (Token = Tok);

      Restore_Scan_State (Scan_State);

      return Result;

   end Next_Token_Is;

   -------------------

   -- No_Constraint --

   -------------------

   procedure No_Constraint is

   begin

      if Token in Token_Class_Consk then

         Error_Msg_SC ("constraint not allowed here");

         Discard_Junk_Node (P_Constraint_Opt);

      end if;

   end No_Constraint;

   ---------------------

   -- Pop_Scope_Stack --

   ---------------------

   procedure Pop_Scope_Stack is

   begin

      pragma Assert (Scope.Last > 0);

      Scope.Decrement_Last;

      if Debug_Flag_P then

         Error_Msg_Uint_1 := UI_From_Int (Scope.Last);

         Error_Msg_SC ("decrement scope stack ptr, new value = ^!");

      end if;

   end Pop_Scope_Stack;

   ----------------------

   -- Push_Scope_Stack --

   ----------------------

   procedure Push_Scope_Stack is

   begin

      Scope.Increment_Last;

      if Style_Check_Max_Nesting_Level

        and then Scope.Last = Style_Max_Nesting_Level + 1

      then

         Error_Msg

           ("(style) maximum nesting level exceeded",

            First_Non_Blank_Location);

      end if;

      Scope.Table (Scope.Last).Junk := False;

      Scope.Table (Scope.Last).Node := Empty;

      if Debug_Flag_P then

         Error_Msg_Uint_1 := UI_From_Int (Scope.Last);

         Error_Msg_SC ("increment scope stack ptr, new value = ^!");

      end if;

   end Push_Scope_Stack;

   ----------------------

   -- Separate_Present --

   ----------------------

   function Separate_Present return Boolean is

      Scan_State : Saved_Scan_State;

   begin

      if Token = Tok_Separate then

         return True;

      elsif Token /= Tok_Identifier then

         return False;

      else

         Save_Scan_State (Scan_State);

         Scan; -- past identifier

         if Token = Tok_Semicolon then

            Restore_Scan_State (Scan_State);

            return Bad_Spelling_Of (Tok_Separate);

         else

            Restore_Scan_State (Scan_State);

            return False;

         end if;

      end if;

   end Separate_Present;

   --------------------------

   -- Signal_Bad_Attribute --

   --------------------------

   procedure Signal_Bad_Attribute is

   begin

      Error_Msg_N ("unrecognized attribute&", Token_Node);

      --  Check for possible misspelling

      Error_Msg_Name_1 := First_Attribute_Name;

      while Error_Msg_Name_1 <= Last_Attribute_Name loop

         if Is_Bad_Spelling_Of (Token_Name, Error_Msg_Name_1) then

            Error_Msg_N -- CODEFIX

              ("\possible misspelling of %", Token_Node);

            exit;

         end if;

         Error_Msg_Name_1 := Error_Msg_Name_1 + 1;

      end loop;

   end Signal_Bad_Attribute;

   -----------------------------

   -- Token_Is_At_End_Of_Line --

   -----------------------------

   function Token_Is_At_End_Of_Line return Boolean is

      S : Source_Ptr;

   begin

      --  Skip past blanks and horizontal tabs

      S := Scan_Ptr;

      while Source (S) = ' ' or else Source (S) = ASCII.HT loop

         S := S + 1;

      end loop;

      --  We are at end of line if at a control character (CR/LF/VT/FF/EOF)

      --  or if we are at the start of an end of line comment sequence.

      return Source (S) < ' '

        or else (Source (S) = '-' and then Source (S + 1) = '-');

   end Token_Is_At_End_Of_Line;

   -------------------------------

   -- Token_Is_At_Start_Of_Line --

   -------------------------------

   function Token_Is_At_Start_Of_Line return Boolean is

   begin

      return (Token_Ptr = First_Non_Blank_Location or else Token = Tok_EOF);

   end Token_Is_At_Start_Of_Line;

end Util;